Examples of the plate-type heat exchanger element conventionally employed for an air-conditioning ventilation fan include a total heat exchanger element which employs as its partition a material having heat transfer properties and permeability to water vapor, such as paper, and a sensible heat exchanger element which employs as its partition a heat-conducting substance that is non-permeable to water vapor, such as a metal or plastic. These conventional heat exchanger elements are generally low in efficiency, since these heat exchanger elements effect a total heat exchange operation or sensible heat exchange operation through the partitions between a supply air flow and an exhaust air flow which continuously pass simultaneously and alternately through their respective layers defined by the partitions of the heat exchanger elements in their respective fixed directions.
On the other hand, in the case of a regenerative rotary type heat exchange operation making use of the accumulation of heat and moisture in a cylindrical-shaped heat exchanger, the cylindrical-shaped heat exchanger is generally required to rotate at a number of revolutions of about 15 r.p.m. since such heat exchanger has a small heat accumulation capacity. For this reason, noise is easily generated by the rotation of the cylindrical-shaped heat exchanger. Further, in the total heat exchange operation, the effective quantity of water vapor adsorbed by the elements constituting the cylindrical-shaped heat exchanger is disadvantageously reduced due to the influence on the cylindrical-shaped heat exchanger of the accumulated sensible heat, the heat of adsorption and the heat of desorption.